This invention relates to a valve which is utilised to control the delivery of liquid into a reservoir whereby the volume of liquid in the reservoir is controlled by the valve through the use of a float which is supported on the liquid.
It is conventional practice to provide float controlled valves whereby the float is associated with a bearing member which is caused to move as a result of movement of the float resulting from variations in water level and where the bearing member acts upon the valve member to cause it to move into and out of engagement with the valve seat. As a result arrangements must be provided to ensure that the degree of force which can be exerted on the valve seat by the bearing member is sufficient to ensure positive closure of the valve and to maintain the valve in the closed position and in some instances provide a means of supplementing that force to ensure that the valve member remains closed. In addition, in the event of a minor variation in the level of the water being sensed by the float, the valve will be caused to open. Therefore, if there are variations in water level resulting from wave action in the reservoir, this can result in rapid periodic opening and closing of the valve which can be destructive to the delivery line for the reservoir and to the valve. In addition the valve will be caused to open when only a small volume is withdrawn form the reservoir.
It is an object of the present invention to overcome at least some of the previous difficulties of the prior art.
Accordingly, the invention resides in a valve comprising a body having an inlet adapted to be connected to a pressurised source of liquid and an outlet which is to communicate with a reservoir, a valve seat between the inlet and outlet, a valve member movable relative to the valve seat between an open and closed position, said valve member having a first face which is movable to be in opposed relation to the valve seat and to be engaged with the valve seat when the valve is in the closed position, said valve member having a second face located in opposed relation to the first face, a chamber located between the body and the second face, a first passageway providing communication between the first face and the chamber, the said chamber having a discharge outlet, a control means associated with the discharge outlet, said control means being controlled by a bearing member adapted to be associated with a float member to be supported in the liquid in the reservoir, said bearing member being adapted to cause the control means to close the discharge outlet when the bearing member is at a first position corresponding to the surface of the liquid in the reservoir when at an upper level and to open the discharge outlet when the bearing member is at a position corresponding to the surface of the liquid in the reservoir when at a lower level, said second face having a greater area than the area defined on the first face by the valve seat.
According to a preferred feature of the invention, the first passageway is provided through the valve member.
According to a further preferred feature of the invention, the control means includes a closure member slidably supported in the body in opposed relation to the discharge outlet to be movable between a closed position at which it is in sealing engagement with the discharge outlet to close the discharge outlet and an open position at which it is clear of the discharge outlet to open the discharge outlet said bearing member being associated with the closure member to cause movement of the closure member between the closed and open position.
According to a further preferred feature of the invention, the control means includes a shuttle member movably supported in the body to define said chamber, said shuttle member having said discharge outlet, said shuttle member being moveable in the body between two end positions comprising an innermost position and an outermost position, said closure member being engagable with the outer end of the shuttle member and being movable with the shuttle member between its end positions wherein when the shuttle member is in its innermost position, the bearing member is at a position corresponding to the upper level of liquid in the reservoir and when the shuttle member is in its outermost position, the bearing member is in a position corresponding to a liquid level intermediate of the upper and lower level of liquid in the reservoir.
According to a preferred feature of the previous feature the shuttle member is biased to its inner most position.
According to a further preferred feature of the invention, the valve member is biased into the closed position.
According to the a further preferred feature of the invention, the bearing member comprises an arm pivotally supported from the body and having a first end spaced to one side of the pivot which is associated with the control means and a second end to the other side of the pivot which is adapted to be mounted to a float supported on said liquid.
According to a preferred feature of the invention the valve member is slidably and sealingly received in said body. According to one embodiment the space defined between the opposed faces of the valve member and the body which are in a slidable relationship with each other are isolated from the inlet and the chamber. According to a feature of the embodiment the outer edge of the second face supports a seal which is in slidable sealing engagement with the body and a flexible diaphragm is mounted between the body and the valve member intermediate of the first and second face, said diaphragm enabling movement of the valve member between the open and closed position, said space being defined between the seal and the diaphragm.
According to a preferred feature of the invention the valve member is at least partially supported from the body by a diaphragm to isolate the inlet from the chamber and the valve is movable within the body with the flexing of the diaphragm.
According to a preferred feature of the previous feature the shuttle member is biased to its inner most position.
According to a further preferred feature of the invention, the valve member is biased into the closed position.
According to a preferred feature of the invention the shuttle member comprises a member slidably and sealingly supported by the body. According to an embodiment of the invention the discharge outlet comprises a passageway through the shuttle member.
According to a preferred feature of the invention the shuttle member comprises a second diaphragm supported from the body. According to an embodiment of the invention the discharge outlet comprises an opening through the second diaphragm.
The invention will be more fully understood in the light of the following description of several specific embodiments.